The following problems may occur regarding a shield structure around contact sensor element: (1) Heat is taken by the shield structure at the time of contact with particles. Accordingly, contact detection sensitivity is reduced. (2) If the projection of shield structure (in the direction of the disk) is smaller than the projection of the contact sensor element, particles may pass the shield structure and collide with the contact sensor element. Accordingly, the contact sensor element may become damaged. (3) If the projection of shield structure (in the direction of the disk) is smaller than the projection of the contact sensor element, the contact sensor element may not contact the disk. Accordingly, contact detection sensitivity may fall. (4) When particles contact shield structure, the shield structure is dragged by the particles. An electrical short between the shield structure and the contact sensor element, or the shield structure and an electrode of contact sensor element may result in damage to the contact sensor element.
The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted.